The present invention relates to an automatic apparatus in the form of a pre-assembled programmable operative unit for the storage, delivery and mixing of metered quantities of fluid substances, used for example during the preparation of dyeing baths, dyeing substances and the like, by means of which it is possible to group together and manage in a small area, a plurality of storage tanks and the associated means for supplying metered quantities of the various substances which must be mixed, under the control of a logic processing unit.
During the preparation of mixtures from fluid substances, for example during the preparation of dyes for the textile industry, paints and auxiliary agents in general, the individual substances or individual ingredients to be mixed are contained in respective storage tanks from which they are taken in metered quantities which are controlled by means of weighing operations.
For this purpose, various apparatuses have been developed, as a result of which it is possible to deliver automatically and mix metered quantities of the various substances, removing them in a controlled manner from the respective storage containers. The documents U.S. Pat. No. 4,526,215, EP-A-0,344,521, EP-A-0,537,434 describe some examples of automatic metering apparatuses which can be used in different application sectors.
In particular, EP-A-0,344,521 describes a metering and mixing plant comprising a plurality of tanks arranged at a suitable distance from one another on a fixed support structure which extends along a path for a carriage provided with a container into which in each case the metered quantities of the individual substances are poured, said substances being subsequently introduced into a mixer located underneath the path of the carriage supporting the container. Each tank is provided moreover with a screw feeder which discharges said substances into an auxiliary container tiltably supported by a weighing device, underneath which the container is arranged in order to receive the substances to be mixed. This solution requires on-site assembly of the entire plant which, once installed, cannot be displaced or removed; moreover, said plant is extremely complicated and difficult to manage and cannot be used in those applications where extremely precise doses are required, both owing to the unreliable nature of the screw metering system and on account of the possible accumulation of errors of the various weighing devices associated with the individual tanks. Moreover, the operating cycle of the entire plant is difficult to manage since residual quantities of the substances to be mixed could remain in the various weighing containers, as well as in the actual movable receiving container, thus altering the mixing conditions.
The document U.S. Pat. No. 4,526,215 illustrates an apparatus for the metering and mixing of fluid substances, in particular paints, comprising a fixed rack provided with a plurality of storage containers, each of which is provided with a delivery valve suitably operated by a support carriage for a receiving container, movable in front of the rack. A weighing scale is mounted on the carriage and is connected to a processing unit. Each container is provided moreover with a respective stirrer which performs mixing after the delivery of each component. This solution also involves installation in a fixed manner, being extremely complicated and costly and unsuitable for applications where it is required to perform the metering of variable quantities of the substances to be mixed, for example for the filling of drums with a capacity of between 10 or 20 and a few hundred litres.
An apparatus for the delivery and metering of fluid substances is also known from the document EP-A-0,537,434 and comprises a plurality of tanks mounted on a bridge structure fixed to the floor. Each container is provided with a delivery head aligned along a travel path for a carriage transporting a receiving container located on weighing scales controlled by a logic processing unit. When the receiving container is completely full, the container must be removed and transferred into another working station for the mixing stage. Although the aim of this patent is to provide an automatic apparatus of limited dimensions, suitable for small or medium-size users, it is still bulky from a structural point of view and also requires long and complicated assembly and set-up operations on-site before it can be used.
In general, the known apparatuses involve the fixed installation of the various components, which must be performed on the actual site where the apparatus is to be used and which does not allow any subsequent modification or displacement of the entire apparatus so that it can be adapted to new or variable requirements as regards use of the apparatus itself. All this requires moreover the separate dispatch of the various components, their assembly on-site and the need to carry out time-consuming verification and setting up of the apparatus, following installation.
A scope of the present invention is to provide an apparatus for the delivery and metering of fluid substances to be mixed, particularly suitable for the preparation of dyeing substances, for example for the textile industry or for other applications, said apparatus having an extremely compact structure as a result of which it is possible to perform the entire mixture preparation cycle, from the delivery of metered quantities of the individual substances to mixing thereof, in a short time restricting the entire assembly to an extremely small area which can be easily monitored or accessed by an operator.
A further scope of the present invention is to provide an apparatus as described above, which can be easily transported and installed in a perfectly operational, ready-assembled condition, i.e. which can be displaced subsequently so as to adapt it to the various requirements of a user, without having to perform on-site disassembly or reassembly of the apparatus.
A further scope of the present invention is to provide an apparatus of the above-mentioned kind, provided with a metering system comprising a single metering unit which can be selectively connected to a plurality of storage tanks grouped together in a compact manner, so as to ensure precise metering of the various substances to be mixed, with reliable and safe operating conditions in any working environment.